Minimally Conscious State

Key Features

• A disorder of severely altered consciousness in which minimal but definite behavioral evidence of self- or environmental awareness is demonstrated

• Distinct from locked-in syndrome and persistent vegetative state

• Often follows major head trauma

• May be temporary or permanent

• Little information is available about its natural history or long-term outlook, which reflects the underlying cause

• The likelihood of functional recovery diminishes with time; after 12 months, patients are likely to remain severely disabled and without a reliable means of communication

Clinical Findings

• Inconsistent evidence of consciousness

• There may occur some degree of functional recovery of behaviors suggesting self- or environmental-awareness, such as

  • Basic verbalization or context-appropriate gestures

  • Emotional responses (eg, smiling) to emotional but not neutral stimuli

  • Purposive responses to environmental stimuli (eg, a finger movement or eye blink apparently to command)

Diagnosis

• Diagnosis usually made on clinical grounds

  • Functional imaging studies show that overall cerebral metabolism is less than in individuals with conscious awareness (20–40% of normal) but slightly higher, though comparable to, those in a persistent vegetative state

  • Functional MRI studies show some auditory network cortical activation in response to familiar voices

Treatment

• Amantadine (100–200 mg orally daily) may hasten recovery when given to patients in a minimally conscious or vegetative state 4–16 weeks after a traumatic brain injury

• Otherwise, there is no evidence for any other measures that can alter the course of the recovery

• Supportive care initially, which may include temporary endotracheal intubation and mechanical ventilation for airway protection, as well as liquid artificial nutrition by nasogastric or percutaneous gastrostomy tube

• Palliative care and/or ethics committee consultation to assist families and clinicians in medical decision-making